Recently, the use of high dielectric substances and ferroelectric substances as the capacitor dielectric film is noted.
However, in the case that a high dielectric substance or a ferroelectric substance is used simply as the dielectric film, it is often that oxygen in the dielectric film is reduced with hydrogen in the steps following the formation of the dielectric film, and the capacitor cannot have good electric characteristics.
As techniques for preventing the deterioration of the dielectric film with hydrogen, the technique of forming an aluminum oxide film, covering the capacitor, and the technique of forming an aluminum oxide film on the inter-layer insulation film formed on the capacitor are proposed. Aluminum oxide film has the function of preventing the diffusion of hydrogen. Owing to this function, the proposed techniques can prevent the arrival of the hydrogen at the dielectric film, and the deterioration of the dielectric film with the hydrogen can be prevented. These techniques are disclosed in, e.g., Patent Reference 1.
[Patent Reference 1]
Specification of Japanese Patent Application Unexamined Publication No. 2002-176149